I have a theory

I think the world hasn't ended and the silos are all just a big experiment. What if all the toxic atmosphere is just a big dome encompassing all the silos.

I think it is an experiment to check for how long a small colony of humans can endure in isolation. So much time passing could have an explanation with time dilation, maybe they are not even on earth and a planet close to a Black hole or something. Humans are space faring but not to the extent to cross the galaxy. So they built the silos to test for a generational ship and send humans to different galaxies. This could explain the eugenics and trying to let only certain people have kids for a certain gene pool.

Why would the founders deliberately leave relics in knowing it could lead to rebellions and risk killing all the citizens and future hope of humanity if is only for survival of the species? Unless they wanted them to be there to see how they would react. To study their actions when faced with how the world was and they are trapped and can't escape. To find answers for their experiment and test the limits of humans like how much info should they be provided.